1. Field of the Invention
The present invention relates to a fluid dispensing system specifically designed to deliver multidose sterile, or homogenized and pasteurized, chemical preservative, antibacterial or antimicrobial additive free (hereinafter known collectively as "preservative free") solutions. More, specifically, the present invention is directed to a fluid dispensing system with a dual self-sealing valve system to dispense multidose sterile solutions in a dropwise form. The dual self-sealing valve system and hydrophobic air filter protects the solutions from contamination after multidose dispensing without the use of preservatives.
2. Description of the Prior Art
Large number of solutions including those that are sold and administered as over-the-counter ("OTC") and/or prescription preparations, such as ophthalmic pharmaceutical, contact lens solutions, drop-administrated medicines for the ear or nose, and some consumer health care liquid solutions, such as creams, gels and lotions, must be kept sterile to prevent contamination from bacteria or other microbes. The conventional means of preventing such contamination is to add a preservative or other antibacterial agent to the solution during packaging. Commonly used preservatives include benzalkonium chloride, methyl parabens, propyl parabens, thimerosal and chlorobutanol. Commonly used antibacterial agents include saline formulations. While these preservatives keep the enclosed solution sterile, the bottle itself may harbor external bacterial or microbial growth which is carried along with the outflow of fluids. In addition, the preservatives themselves are often toxic, not just to bacteria or microbes, but also to the cells which are being treated by the bottled solution. For example, the preservatives used in most eye drops can disrupt the corneal epithelium, irritate conjunctival tissues and cause allergic reactions. Because of this toxicity level, continued use can cause more long-term problems than the solutions solve.
Furthermore, squeezable dispensing bottles containing saline formulations in the dispensing liquids may be provided with nozzles including filter membranes which are permeable to the dispensed liquid as well as being permeable to the air which must be aspirated through the nozzle to replace the dispensed liquid and reinflate or re-expand the container. However, the filter membrane must be impermeable to bacteria in order to prevent the aspirated air from carrying bacteria into contact with the stored solution, and contaminating the solution due to repeated dispensing. Yet, filter membrane materials which are sufficiently hydrophilic to permit permeation of the saline solution often permit retention of the saline solution on the filter so that the retained solution increases the resistance of the filter to passage of the aspirating air. The partially obstructed flow of aspirating air not only retards the re-expansion of the squeezed bottle wall, but also impedes repeated squeezing of the bottle when large quantities of the solution must be dispensed. When portions of the filter are treated to repel the solution and improve air passage, the solution can sometimes leach the treating composition from the filter.
In addition, consumer food products, such as milk and dairy products, must be kept refrigerated to reduce the contamination and/or action of bacteria or other microbes.
Container contamination can also be the result of particulate matter being drawn back into the container with the liquid in the dropper tip that has not been delivered as a drop. Over several drop deliveries, for example, in dusty conditions, a significant accumulation of dust in the container is possible.
Despite these and other problems with filter bottles, and the use of preservatives in dispensing liquids, various designs for liquid dispenser for sterile solutions have been reported.
U.S. Pat. No. 4,938,389 describes a dispenser including a filter assembly having a hydrophobic filter and a hydrophilic filter in tandem with the hydrophobic filter located near the dispensing tip.
U.S. Pat. No. 3,760,987 describes a snap assembled dispensing package and cover made up of a container which has a tapered shank on its discharge end and a piercing device, snappably connected to the container, which also serves as a conduit for dispensing the medicament. The dispensing package further contains an air filter and a solution filter.
U.S. Pat. Nos. 4,917,271 and 3,149,758, and WO 90/15015 all teach dispensing devices with single filtering membranes or composite membranes where a portion of the membrane is hydrophobic and another portion of the membrane hydrophilic.
U.S. Pat. No. 4,463,880 describes a medicine drop dispenser with a single hydrophobic and microporous antibacterial filter that provide a barrier to the ingress of bacteria and for permitting the egress of sterile liquid.
U.S. Pat. No. 4,533,068 describes sterile solution delivery and venting devices including a positive acting, normally closed check valve which opens to express solution from the package when squeezing pressure is applied and which automatically closes when the pressure is released. A hydrophobic filter is included to sterilize the replacement air which enters the package upon release of the squeezing pressure.
U.S. Pat. No. 2,684,789 describes seal cap and dispensing nozzle for tubes or bottles having a self-closing dispensing valve.
U.S. Pat. No. 3,176,883 describes a fluid dispenser of the squeeze bottle type having an air vent post extending to the side of the dropper tip and directly above the lip of the container.
U.S. Pat. Nos. 4,739,906, 4,234,103 and 4,773,551 all describe bottles with caps containing a protuberance for closing the hole in the dropper tip.
It would be desirable to provide a convenient, economical and safe fluid dispensing system for the delivery of sterile preservative free solutions.
Accordingly, it is an object of the present invention to provide an improved sterile solution delivery and fluid dispensing system of the type set forth.
It is a another object of the present invention to provide a multidose fluid dispensing system which can protect the solutions from contamination under prolonged and repeated use without the use of preservatives.
It is another object of the present invention to provide a multidose fluid dispensing bottle for dispensing ophthalmic pharmaceutical, contact lens solutions, consumer health care liquid solutions and consumer food product solutions which provide good flow properties and protection against bacterial or microbial contamination.
Another object of the present invention is to provide a multidose fluid dispensing bottle which can be used to dispense medicine solutions, which do not contain preservatives, in substantially uniform drops.
It is another object of the present invention to provide a novel fluid dispensing system which incorporates positive acting, normally closed, valve means in combination with a hydrophobic membrane air sterilizing filter means.
It is another object of the present invention to provide a novel fluid dispensing system which incorporates two positive acting, normally closed, valve means in series and in combination with a hydrophobic membrane air sterilizing filter means.
It is another object of the present invention to provide a novel fluid dispensing system having a container with a system outlet and an air passageway, positive acting, normally closed, valve means positioned between the system fluid outlet and a hydrophobic filter positioned at the end of the air inlet passageway, the valves means being openable upon the application of pressure built up within the container and being automatically sealed upon release of the pressure.
Other objects and advantages of the invention will become apparent from the following detailed disclosure.